Bicycle

ABSTRACT

The invention relates to a bicycle adjusting device, in particular an adjusting device for adjusting the height of the front wheel suspension, the rear wheel suspension, the saddle or of the steering mechanism of a bicycle, e.g. of a mountain bike, a bicycle with at least one bicycle adjustment device, as well as a bicycle-steering head bearing system, whereby the adjustment has at least one double-acting piston-cylinder assembly with a first cylinder space ( 14   a,    34   a ) and a second cylinder space ( 15   a,    35   a ) in each case, and whereby the two cylinder spaces of the two adjustment devices are interconnectable by means of a fluid duct fitted for that purpose.

This Application is a National Phase of International Application No.PCT/EP02/06133, filed on Jun. 4, 2002, which claims priority from GermanPatent Application No. 201 11 247.7, filed on Jul. 6, 2001; GermanPatent Application No. 202 02 656.6, filed on Feb. 20, 2002; and GermanPatent Application No. 202 05 643.0, filed on Apr. 11, 2002.

The present invention relates to a bicycle adjusting device, inparticular a device for adjusting the height of the front wheelsuspension, the rear wheel suspension, the saddle or of the steeringmechanism of a bicycle, e.g. of a mountain bike or a bicycle with atleast one bicycle adjustment device, as well as a bicycle steering headbearing system.

With conventional bicycles the height of the front wheel suspension, therear wheel suspension, the saddle or the steering mechanism are notadjustable at all or only adjustable with difficulty.

The invention is aimed at providing a novel bicycle adjustment deviceand/or a novel bicycle, as well as a novel bicycle steering head bearingsystem.

The invention achieves the above and further aims by means of theobjects in Claim 1. Advantageous developments of the invention arecontained in the subsidiary claims.

When the bicycle adjustment device described in this invention isinstalled in a bicycle, the user of the bicycle can easily adjust thebicycle geometry to suit current conditions. For instance, the height ofthe front and/or rear wheel suspension may be changed while the bicycleis in use, preferably while being ridden.

The new adjustment device described in this invention is particularlysuited to mountain bikes. For instance, the front wheel may be retractedwhile riding uphill with the mountain bike, and extended again whenriding downhill. Alternatively and additionally the rear wheel may beextended while riding uphill and retracted again while riding downhill.

By shifting the rider's center of gravity further back, the risk of therider pitching forward and/or overloading the arms and wrist joints isreduced. When riding uphill, the center of gravity of the rider mayagain be moved forward. In this way the power transmission effort ismore efficiently applied while an uncomfortable and taxing elevation ofthe front wheel is avoided.

This present application relates to the international application PCT/EP01/00074 by the same applicant, which has been made fully public bybeing incorporated in this present application.

Below, the invention is explained in more detail by means of furtherembodiments and illustrations. The illustrations show:

FIG. 1 an adjusting device according to a first embodiment example ofthe invention in longitudinal section;

FIG. 2 a an adjusting device according to a second embodiment example ofthe invention in longitudinal section;

FIG. 2 b a perspective view of the adjustment device shown in FIG. 2 a

FIG. 2 c a detailed representation of the top section of the plunger inlongitudinal section as shown in FIGS. 2 a and 2 b.

FIG. 3 an adjusting device according to a third embodiment example ofthe invention in longitudinal section;

FIG. 4 a detailed representation of the switch shown in FIGS. 2 a, 2 b,2 c, and used in the adjustment device shown in FIG. 3;

FIG. 5 a an adjusting device according to a fourth embodiment example ofthe invention in longitudinal section;

FIG. 5 b a perspective view of the adjustment device shown in FIG. 5 a;

FIG. 5 c a detailed representation of the upper part of the plungershown in FIGS. 5 a and 5 b in longitudinal section;

FIG. 6 an adjusting device according to a fourth embodiment example ofthe invention in longitudinal section;

FIG. 7 a detailed representation of an alternative embodiment example ofthe switch as shown in FIGS. 2 a, 2 b, 2 c, and as used with theadjustment device shown in FIG. 3;

FIG. 8 a bicycle with two adjustment devices according to an embodimentexample of the invention in longitudinal section;

FIG. 9 a perspective representation seen from the front right of abicycle steering head bearing system to which two legs of a front forkand a steering assembly have been fitted;

FIG. 10 a perspective representation, seen from the front left, of thebicycle steering head bearing system shown in FIG. 9 with the steeringassembly fitted, but without the fork legs;

FIG. 11 a longitudinal section through the steering head bearing system,with fork legs and steering mechanism fitted as shown in FIGS. 9 and 10;and

FIG. 11 b a detailed view of part of a longitudinal section of thesteering head bearing system shown in FIG. 11 a.

In FIG. 1 a device for adjusting the height of the front wheelsuspension of a bicycle according to an embodiment example of thepresent invention is shown. A pneumatic cylinder 30 a is attached at itsbottom end to a guide tube 37 a by means of a threaded connection. Atube 37 b with a piston rod 32 a attached to it, is fitted to a steeringunit 7 a, which consists of handlebars, steering tube and (fork) yoke. Apiston 31 a that is sliding fit in the pneumatic cylinder 30 a is fittedto the bottom end of the piston rod 32 a. The tube 37 b and the pistonrod 32 a are longitudinally adjustable in relation to the guide tube 37a and the pneumatic cylinder 30 a, i.e. in the direction of the arrow A.

The first cylinder space 34 a, i.e. the “plus chamber”, is formed by thepneumatic cylinder 30 a. The second cylinder space 35 a, i.e. the “minuschamber”, is an annular cylinder space, formed by the pneumatic cylinder30 a, the piston rod 32 a and the piston 31 a. The bottom outside areaof the piston 31 a that delimits the first cylinder space 34 a at thetop is larger than the annular top outside area of the piston 31 a thatdelimits the second cylinder space 35 a at the bottom.

A connecting hole, which can be opened or shut by means of a valve, hasbeen provided in the piston 31 a, which connects the first cylinderspace 34 a with the second cylinder space 35 a. The valve is connectedto an actuator 85 a, which is raised to the level of the steering unit 7a by the piston 31 a and/or the piston rod 32 a. At the level of thesteering unit and/or handlebars the actuator 85 a has an actuatorelement 86 a. When it is actuated, the valve opens and/or shuts.

When the valve is shut, an equalization of forces between the “pluschamber” and “minus chamber” takes place at piston 31 a, whereby thepiston 31 a, the piston rod 32 a and the tube 37 b take up a particularsetting in relation to the guide tube 37 a and the pneumatic cylinder 30a, for instance the setting shown in FIG. 1. When the valve is opened,the “plus chamber” 34 a and the “minus chamber” 35 a are interconnected,so that an equalization of pressure between the chambers can take place.The piston 31 a, the piston rod 32 a and the tube 37 b move upwards inrelation to the guide tube 37 a and the pneumatic cylinder 30 a, in thedirection of the arrow A. When the valve is shut again, an equalizationof forces again takes place at piston 31 a between the “plus chamber”and “minus chamber”, whereby the piston 31 a, the piston rod 32 a andthe tube 37 b take up a second setting in relation to the guide tube 37a and the pneumatic cylinder 30 a, e.g. a setting that lies above thatshown in FIG. 1. In this setting the bicycle is particularly well suitedto downhill riding.

For uphill riding the valve is opened again, and the piston 31 a, thepiston rod 32 a and the tube 37 b pushed down again by the bicycle riderin relation to the guide tube 37 a and the pneumatic cylinder 30 a, inthe direction of the arrow A. This may be achieved for instance by theuser of the bicycle applying downward pressure on the steering unit 7 ain the direction of Arrow B. When the valve is re-shut, an equilibriumof forces again takes place at piston 31 a between “plus chamber” 34 aand “minus chamber” 35 a, whereby the piston 31 a, the piston rod 32 aand the tube 37 b assume a third setting in relation to the guide tube37 a and the pneumatic cylinder 30 a, that for instance lies below thesetting shown in FIG. 1. In this setting the bicycle is particularlywell suited to uphill riding.

At the bottom end of the pneumatic cylinder 30 a an element 33 a ofelastic material is fitted. Over it is a float body 38 a that seals offthe first cylinder space 34 a from the cylinder space in which theelastic element 33 a is fitted.

FIGS. 2 a, 2 b and 2 c show an adjusting device according to a furtherembodiment example of the present invention. In FIG. 2 b a pneumaticcylinder 10 a is shown, connected at its lower end to a wheel suspension(not shown), to which the front wheel of a bicycle is attached. Apiston-shaped plunger 17 b, of which the lower, wider end section 17 cslides into the pneumatic cylinder 10 a according to FIG. 2 a, isattached to the steering unit (not shown) consisting of handlebars,steering tube and (fork) yoke of the bicycle. The plunger 17 b and thepneumatic cylinder 10 a both show a perfectly circular outline incross-section, with the outside diameter of the lower end section 17 cof the plunger 17 b essentially the same as the inside diameter of thepneumatic cylinder 10 a. The plunger 17 b is longitudinally adjustablein relation to the pneumatic cylinder 10 a, i.e. in the direction ofarrow A.

The outside wall of the pneumatic cylinder 10 a encloses a firstcylinder space 14 a, which forms the “plus chamber”. The “plus chamber”14 a is delimited at the bottom by the floating piston 19 a, and at thetop by the underside of the lower end section 17 c of the plunger 17 b.To seal the “plus chamber” 14 a at the lower end, O-ring seals 19 c havebeen provided on the outside wall of the float piston 19 a, seated incorresponding machined annular grooves in the float piston 19 a.Similarly, O-ring seals 19 b, seated in corresponding machined annulargrooves on plunger 17 b, have been provided on the outside wall of thelower end section 17 c of the plunger 17 b, for sealing the “pluschamber” 14 a at the upper end.

The outer wall of the pneumatic cylinder 10 a also encloses a second,annular cylinder space 15 a, which forms the “minus chamber”. The “minuschamber” 15 a is delimited at its bottom end by the annular upper sidesof the bottom end section 17 c of the plunger 17 b; at its top by anO-ring seal 17 d attached to the pneumatic cylinder 10 a, and to theinside by the outside wall of a central, thinner section 17 a of theplunger 17 c. Surrounding O-ring seals 19 b have been provided on theoutside and inside walls of the seal 17 d, seated in correspondinglymachined annular grooves in the seal 17 d in order to seal the “minuschamber” 15 a at the top. The central, narrower section 17 a of theplunger 17 c is a sliding fit in the circular central opening of theseal 17 d, and is adjustable in a longitudinal direction in relation tothe seal 17 d, i.e. in the direction of the arrow A.

The area of the bottom end section 17 c of the plunger 17 b delimitingthe first cylinder space 14 a at the top, is larger than the area of theannular upper side of the bottom end section 17 c of the plunger 17 bthat delimits the second cylinder space 15 a at the lower end.

A first hydraulic line 16 a runs longitudinally through the center ofthe plunger 17 b, which is connected at the bottom to the “plus chamber”14 a. The first hydraulic line 16 a has an essentially circular crosssection. A second hydraulic line 16 b, which is connected at the bottomto the “minus chamber” 15 a, e.g. via corresponding drilled holes, alsoruns longitudinally through the plunger 17 b. The second hydraulic line16 b has an annular cross-section and is separated from the firsthydraulic line 16 a by means of tubular intermediate element 18.

At the top of plunger 17 there is a check valve 19, through which airfrom the outside can be pumped into the first hydraulic line 16 a, andinto the “plus chamber” 14 a. The check valve 19 prevents the air fromescaping again to the outside from the “plus chamber” 14 a and the firsthydraulic line 16 a. According to FIG. 2 c the first hydraulic line 16 ais connected via a horizontal aperture 13 a to the first hose shown inFIG. 2 a at the top of the plunger 17 b, and according to FIG. 2 c thesecond hydraulic line 16 b via a horizontal aperture 13 b to the secondhose 12 b shown in FIG. 2 a. There is a switch 11 between the two hoses12 a, 12 b that performs the function of a valve between the hoses 12 aand 12 b. A hydraulic connection can be established between the hoses 12a and 12 b by means of the switch 11, or hose 12 a can be hermeticallyseparated from 12 b.

When switch 11 is closed, i.e. when the connection between hoses 12 aand 12 b is broken, an equalization of forces occurs between the “pluschamber” 14 a and the “minus chamber” 15 a at the lower end section 17 cof plunger 17 b, whereby plunger 17 b assumes a first setting inrelation to pneumatic cylinder 10 a. When switch 11 is opened, the “pluschamber” 14 a and the “minus chamber” 15 a are interconnected via thefirst hydraulic line 16 a, as are the first hose 12 a, the second hose12 b and the second hydraulic line 16 b, so that an equalization ofpressure can take place between the chambers 14 a and 15 a. The plunger17 b then moves upwards in the direction of arrow A in relation to thepneumatic cylinder 10 a. When the switch 11 is closed again, anequalization of forces between the “plus chamber” and “minus chamber”again takes place at the lower end section 17 c of the plunger 17 b,whereby the plunger 17 b assumes a second setting in relation to thepneumatic cylinder, e.g. the setting shown in FIG. 2 a. In this settingthe bicycle is particularly well suited to riding downhill.

For uphill riding the switch 11 is opened again, and the plunger 17 bpressed downward in relation to the pneumatic cylinder 10 a in thedirection of the arrow A by the user of the bicycle. When switch 11 isclosed again, an equalization of forces between the “plus chamber” and“minus chamber” again takes place at the lower end section 17 c of theplunger 17 b, whereby the plunger 17 b assumes a third setting inrelation to the pneumatic cylinder 10 a, which for instance lies belowthe setting shown in FIG. 2 a. In this setting the bicycle isparticularly well suited to riding uphill.

An upper, wider end section of the float piston 19 a is a sliding fit inthe pneumatic cylinder 10 a. In the same way, the lower end section ofthe float piston 19 a is sliding fit in spacer 10 b, which is attachedto the bottom end of the pneumatic piston 10 a. The float piston 19 a isalso adjustable in relation to the pneumatic cylinder 10 a in alongitudinal direction, i.e. in the direction of an arrow B, and servesas a lower shock absorber.

The upper side of the top end section of the float piston 19 thatdelimits the area of the first cylinder space 14 a at the bottom, islarger than the area of the annular underside of the top end section ofthe float piston 19 a that delimits the lower air chamber 14 b at thetop.

A check valve 19 d is fitted at the bottom of the pneumatic piston 10 a,through which air can be pumped from the outside into the lower airchamber 14 b. The check valve 19 d prevents the air from escaping fromthe bottom air chamber 14 b to the outside. In order to seal off thelower air chamber 14 b at the bottom, O-ring sealing elements have beenprovided on the outside wall of the spacer 10 b, fitted in correspondingmachined circular grooves.

As an additional shock absorber, an annular rubber buffer 19 e is fittedat the top end of the spacer 10 b, into the central aperture of whichthe narrower center section of the float piston 19 a is inserted.Alternatively, the rubber buffer 19 e may be dispensed with. The sealingelements 19 c have been arranged in such a way that a stop provided onthe pneumatic cylinder 10 a prevents the float piston 19 a from beingable to be shifted up too high.

In FIG. 3 an adjusting device according to a third embodiment example ofthe invention is shown. This is identical to the adjustment deviceillustrated in connection with FIG. 2 a, 2 b, 2 c, except that insteadof the shock absorber installed there—formed by the float piston 19 aand the rubber buffer 19 e—several superimposed annular elastomers 29 f,29 g, 29 h, 29 i are used as shock absorbers. Spacer discs 22 a, 22 b,22 c are located between each two elastomers 29 f, 29 g, 29 h, 29 i.Each spacer disc 22 a, 22 b, 22 c has a flange at the top and bottom,which all fit into the central aperture of an elastomer 29 f, 29 g, 29h, 29 i. A float body 21 is fitted over the uppermost elastomer 29 f toseal off the “plus chamber” 24 a that is enclosed by the pneumaticcylinder 20 a at the bottom—e.g. by means of a seal, in particular anO-ring. Alternatively the float body 21 can also be arranged in such away that the float body 21 does not seal off the “plus chamber” 24 a atthe bottom (and neither do the elastomers 29 f, 29 g, 29 h, 29 i and thespacer discs 22 a, 22 b, 22 c), and/or the float body-seal (and/or theelastomer 29 f, 29 g, 29 h, 29 i and spacer discs 22 a, 22 b, 22 c)is/are made semi-permeable to air. In this way it can be achieved thatair between the spaces lying above and under the float body 21 can beexchanged (and where necessary also between the various spaces lyingunder the float body 21). Sealing the “plus chamber” 24 a at the bottomthen occurs e.g. with the help of the element 29 k at the bottom end. Avalve may also be fitted to it, through which air can be pumped into the“plus chamber” 24.

FIG. 4 shows a detail representation of the switch 11 used in FIG. 2 a,2 b, 2 c, and the adjustment device used in FIG. 3. The switch 11 isattached to the handlebars of the bicycle e.g. by means of a screw.According to FIG. 2 a and FIG. 4, the first hose 12 a is connected to afirst connecting hole 40 a, and the second hose 12 b to a secondconnecting hole 40 b of the switch 11. The first connecting hole 40 a isconnected to a first, cylindrical hollow space 41 a that runs downwardsfrom the upper side of the switch 11. In similar fashion the secondconnecting hole 40 b is connected to a second, cylindrical hollow space41 b. The two hollow spaces 41 a, 41 b are connected to each other via acentral hollow space 41 c, which is tapered to the top in steps.

An upper, wider end section of the switch element 42 is a sliding fit inthe first hollow space 41 a. A middle, narrower section of the switchelement 42 is a sliding fit in the central hollow space 41 c, and abottom, wider end section of the switch element 42 is a sliding fit inthe second hollow space 41 b. This then means that the switch element 42is longitudinally adjustable inside switch 11, i.e. in the direction ofarrow C.

In order to seal off the first hollow space 41 a at the top, O-ring sealelements 45 are provided on the outside wall of the switch element 42,fitted into corresponding machined circular grooves in the switchelement 42.

The lower outside area of the bottom, wide end section of the switchelement 42 that delimits the second hollow space 41 b at the top, islarger than the annular top outside area of the bottom, wider endsection of the switch element 42 that delimit the first hollow space 41a at the bottom. The switch element 42 is forced upwards by thepneumatic forces resulting from this. In the process an annular sealelement 44 is pressed against the annular upper outside area of thebottom, wider end section of the switch element 42, as well as againstan annular lower outside area of a stepped recess of the central hollowspace 41 c. This pneumatically separates the first hollow space 41 afrom the second hollow space 41 b, and therewith also the plus and minuschamber 14 a, 15 a shown in FIG. 2 from the respective hollow spaces 41a, 41 b.

When the switch element 42 is pressed down against the air pressure bythe user of the bicycle in the direction of arrow D, the seal element 44is released, so that air can flow from the first hollow space 41 a viathe central hollow space 41 c into the second hollow space 41 b, or viceversa. When the switch element 42 is again released by the user, it isforced upwards again in the direction of the arrow C by the pneumaticpressure. This causes the first hollow space 41 a to be isolated againfrom the second hollow space 41 b, and therewith also the plus and minuschambers 14 a, 15 a shown in FIG. 2 a connected to the hollow spaces 41a, 41 b.

Instead of the switch 11 shown in FIG. 4, the switch 111 shown in FIG. 7can also be used with the adjustment device shown in FIG. 3 and in FIG.2 a, 2 b, 2 c, for the pneumatic separation of the “plus chamber” andthe “minus chamber”. The switch 111 may for instance be attached to thehandlebars of the bicycle with a switch. The first hose 12 a shown inFIG. 2 a and FIG. 4 can be connected to a first horizontal connectinghole 140 a, and according to FIG. 7, the second hose 12 b to a second,horizontal connecting hole 140 b of the switch 111. The connecting holes140 a, 140 b are connected to a cylindrical hollow space 141 a runningin a longitudinal direction through the switch 111.

A cylindrical lower section of a switch element 142 is a sliding fit inthe hollow space 141 a. The switch element 142 is therefore adjustableinside switch 111 in a longitudinal direction, i.e. in the direction ofarrow C.

In order to seal off the connecting holes 140 a, 140 b from each other,an O-ring seal element 145 a is provided on the outside wall of theswitch element 142, fitted into a corresponding circular groove on theswitch element 142.

In the same way similar O-ring seal elements 145 b, 145 c are providedhigher up and lower down on the outside wall of the switch element 142,also fitted into correspondingly machined circular grooves on the switchelement 142. The seal elements 145 b, 145 c serve to prevent that aircan escape downwards from the bottom connecting hole 140 b via thehollow space 141 a, and upwards from the top connecting hole 140 a airvia the hollow space 141 a.

The hollow space 141 b widens upwards in steps at a top section of theswitch 111. A spring element 146 seats on the top surface of the step. Aselector button 147 is fitted at the top end of the switch element 142,and the spring element 146 presses against its lower end. As shown inFIG. 7, the spring element 146 is wound in a spiral around a similarcylindrical center section of the switch element 142. The tensile forceof the spring pushes the switch element 142 upwards.

When the switch element 142 is pushed down in the direction of arrow Dagainst the spring by the user of the bicycle, the top connecting hole140 a and the bottom connecting hole 140 b are connected to a groove148, which is annularly machined into the switch element 142 between thetop and the bottom seal element 145 a, 145 b. Consequently air can flowfrom the top connecting hole 140 a via the groove 148 into the bottomconnecting hole 140 b, or vice versa. When the switch element 142 isagain released by the user, it is forced upwards in the direction of thearrow C by the spring. As a result the top connecting hole 140 a isagain pneumatically separated from the bottom connecting hole 140 b, andtherewith also the plus and minus chamber 14 a, 15 a. shown in FIG. 2 aconnected to the respective connecting holes 140 a, 140 b.

In FIGS. 5 a, 5 b, 5 c and 5 d an adjusting device according to afurther embodiment example of the present invention is shown. Inrelation to FIG. 5 b a pneumatic cylinder 50 a is attached at its bottomend to a wheel suspension (not shown) that can be attached to the frontwheel of a bicycle. A piston-shaped plunger 57 b is attached to asteering unit (not shown) of the bicycle consisting of handlebars,steering tube and (fork) yoke, of which the lower wider end section 57 cis a sliding fit in the pneumatic cylinder 50 a according to FIG. 5. Theplunger 57 b and the pneumatic cylinder 50 a have essentially circularcontours in cross section, where the outside diameter of the bottom endsection 57 c of the plunger 57 b is essentially similar to the insidediameter of the pneumatic cylinder 50 a. The plunger 57 b is adjustablein a longitudinal direction, i.e. in the direction of arrow A inrelation to the pneumatic cylinder 50 a.

The outside wall of the pneumatic cylinder 50 a encloses a firstcylinder space 54 a, which forms a “plus chamber”. The “plus chamber” 54a is sealed off at the bottom by the float body 61. For this, an O-ringseal element are provided around the outside wall of the float body 61,fitted into a corresponding machined annular groove in the float body61.

In the adjustment device shown in FIGS. 5 a, 5 b, 5 c, 5 d, severalsuperimposed annular elastomers 69 f, 69 g, 69 h, 69 i have been fittedunder the float body 61, to act as shock absorbers as in the adjustmentdevice in the pneumatic cylinder 50 a as shown in FIG. 3. Spacer discs62 a, 62 b, 62 c are fitted between every two elastomers 69 f, 69 g, 69h, 69 i. Each spacer disc 62 a, 62 b, 62 c has flanges at the top andbottom, which fit into the central aperture of an elastomer 69 f, 69 g,69 h, 69 i.

The “plus chamber” 54 a is delimited at the top by the underside of thebottom end section 57 c of the plunger 57 b. For sealing the “pluschamber” 54 a at the top, bring seal elements 59 b have been provided onthe outside wall of the bottom end section 57 c of the plunger 57 b,fitted into corresponding machined circular grooves of the plunger 57 b.

Furthermore the outside wall of the pneumatic cylinder 50 a encloses asecond, annular cylinder space 55 a, which forms one “minus chamber”.The “minus chamber” 55 a is delimited at the bottom by the upper side ofthe bottom end section 57 c of the plunger 57 b, and at the top by anannular seal 57 d, attached to the top of the pneumatic cylinder 50 a,and to the inside by the outside wall of a central, narrower section 57a of the plunger 57 c. In order to seal the “minus chamber” 55 a at thetop, O-ring seal elements 59 b have been provided on the outside andinside walls of the seal 57 d, fitted into corresponding machinedcircular grooves in the seal 57 d. The central, narrower section 57 a ofthe plunger 57 c is a sliding fit in the circular central aperture ofseal 57 d, and is therefore adjustable in a longitudinal direction inrelation to the seal 57 d, i.e. in the direction of the arrow A.

The area of underside of the bottom end section 57 c of the plunger 57 bthat delimits the first cylinder space 54 a at the top is larger thanthe upper areas of the bottom end section 57 c of the plunger 57 b thatdelimit the second cylinder space 55 a at the bottom.

An elongated hollow space 56 b runs longitudinally through the middle ofthe plunger 57 b. The hollow space 56 b has an essentially annular crosssection. A hydraulic line 56 a, adjustable in a longitudinal direction,has been fitted in the hollow space 56 b, which is connected at thebottom to the “plus chamber” 54 a.

According to FIG. 5 c, a valve 59 has been provided at the top of thehydraulic line 56 a, through which air can be pumped from the outsideinto the hydraulic line 56 a, and into the “plus chamber” 54 a. Thevalve 59 prevents the air in the “plus chamber” 54 a, and the hydraulicline 56 a from escaping to the outside again.

According to FIG. 5 d, a bottom, wider end section of the hydraulic line56 a functions as a valve: As shown in FIG. 5 d, the outside area of thebottom, wider end section of the hydraulic line 56 a is tapered upwards(here: in a conical shape). Correspondingly the inside area of thehollow space 56 b near the bottom, wider end section 57 c of the plunger57 b is tapered upwards (here: provided with a step).

By means of the pneumatic force acting on the bottom outside area of thehydraulic line 56 a, the hydraulic line 56 a is forced upwards in thedirection of arrow C In the process an O-ring seal element 59 b isforced against the conical top outside area of the bottom, wider endsection of the hydraulic line 56 a, as well as against the annularbottom inside area of the step provided at the bottom, wider end section57 c of the plunger 57 b. In this way the “plus chamber” 54 a ispneumatically separated from the “minus chamber” 55 a.

When the hydraulic line 56 a is forced down as per FIG. 5 c in thedirection of arrow B against the air pressure by the user of thebicycle, the seal element 59 b is released as per FIG. 5 d so that aircan flow from the “plus chamber” 54 a into the “minus chamber” 55 a, orvice versa. When the hydraulic line 56 a is again released by the user,it is again forced upwards in the direction of arrow C due to thepneumatic pressure as per FIG. 5 d. Due to this, the “plus chamber” 54 ais again pneumatically separated from the “minus chamber” 55 a.

When this takes place, an equalization of forces occurs between “pluschamber” 54 a and “minus chamber” 55 a at the bottom end section 57 c ofthe plunger 57 b, whereby the plunger 57 b assumes a “first” position inrelation to the pneumatic cylinder 50 a, e.g. the setting shown in FIG.5 a.

When the “plus chamber” 54 a and the “minus chamber” 55 a arehydraulically interconnected, as described above, an equalization ofpressure between the chambers 54 a and 55 a can take place. The plunger57 b slides upwards in relation to the pneumatic cylinder 50 a in thedirection of the arrow A. To avoid excessive upwards displacement of theplunger 50 a and/or a violent stopping of the top end of the bottom endsection 57 c of the plunger 57 b against the seal 57 d, an annular shockabsorber 63 has been fitted around the central section of the plunger 57b, above the bottom end section 57 c of the plunger 57 b. The outsidediameter of the shock absorber 63 is smaller than that of the pneumaticcylinder 50 a.

When the “plus chamber” 54 a and the “minus chamber” 55 a are separatedagain, an equalization of forces again takes place between “pluschamber” 54 a and “minus chamber” 55 a at the bottom end section 57 c ofthe plunger 57 b, whereby the plunger 57 b assumes a second position inrelation to the pneumatic cylinder 50 a, lying above the setting shownin FIG. 5 a. In this setting the bicycle is particularly well suited toriding downhill.

For uphill riding, a new connection is established between the “pluschamber” 54 a and the “minus chamber” 55 a, and the plunger 57 b presseddownward by the user of the bicycle in relation to the pneumaticcylinder 50 a, in the direction of the arrow A.

When the connection between the “plus chamber” 54 a and the “minuschamber” 55 a is broken again, an equalization of forces between “pluschamber” 54 a and “minus chamber” 54 b again takes place at the bottomend section 57 c of the plunger 57 b, whereby the plunger 57 b assumes athird setting in relation to the pneumatic cylinder 50 a, e.g. one thatlies below the setting shown in FIG. 5 a. In this setting the bicycle isparticularly well suited to uphill riding.

In an alternative embodiment example, instead of the bottom shockabsorber fitted to the adjustment device as shown in FIGS. 5 a, 5 b, 5c, 5 d (i.e. the elastomers 69 f, 69 g, 69 h, 69 i) an elastomer may befitted around the thinner section 57 a of the plunger 57 c and attachedto the plunger 57 c as a shock absorber (or e.g. also a spring fittedaround the narrower section 57 a of the plunger 57 c). Due to theelastomer or the spring stopping against the top end section of thepneumatic cylinder 50 a, any excessive downward displacement of theplunger 57 b is prevented. Alternatively or additionally a spring may befitted underneath the pneumatic cylinder 50 a and/or the cartridge. Inthis way the cartridge is sprung from the wheel suspension and/or thefork sprung against the road, i.e. is in sprung articulation.

FIG. 6 shows an adjusting device according to a further embodimentexample of the invention. This is identical to the adjustment deviceillustrated in relation to FIG. 5 a, 5 b, 5 c, 5 d, except that thebottom shock absorbers used in that case (i.e. the elastomers 69 f, 69g, 69 h, 69 i), a float piston 69 a and a rubber buffer 69 e (as well asa spacer 69 b and a valve 69 d) can be used as shock absorbers. Thefloat piston 69 a, the rubber buffer 69 e, the spacer 69 b and the valve69 d are identical in construction and in function to the constructionand function of the components illustrated in relation to FIG. 2 a.

FIG. 8 shows a bicycle with frame 1, with a longitudinal rod 2, a saddlerod 3 and a connecting rod 4. A steering head bearing 5 has been fittedto the common ends of the longitudinal rod 2 and the connecting rod 4,to which one end of a front fork 6 and/or a steering assembly 7 attachedto it by a bearing, are connected to the handlebars 8 by a bearing. Thefront fork 6 has two fork legs (of which the illustration only shows thefront fork leg). Each fork leg consists of a piston-cylinder assembly,as illustrated in more detail below.

As an alternative to the embodiment example shown here, a fork with onlyone fork leg may be provided as well.

A front wheel is attached so that it can rotate around the free end 10of the piston-cylinder assembly.

From the piston-cylinder assembly 9 a first central pressurizing line 12and a second central pressurizing line 13 run to a secondpiston-cylinder assembly 14, in which a check valve 15 has been fittedto the first central pressurizing line 13. No check valve has beenprovided in the second central pressurizing line 13.

A housing end section 17 of the second piston-cylinder assembly 14 isconnected to the connecting rod 4 by means of a swivel joint 18.

A piston rod 19 of the second piston-cylinder assembly is connected tothe rear end of the spring element 20 (which is shown on the right-handside in the illustration), here a single coil spring. One end 21 of thespring element 20 is connected by means of a swivel joint 22 to a swingarm rear wheel suspension 23, here consisting of three interlinked rods24, 25, 26, of which the swing arm is designed to provide a rotatablemounting for the rear wheel 27.

The swing arm rear wheel suspension 23 is connected to saddle rod 3 bymeans of a swivel joint 28, at the free end of which a saddle 3 a isattached. Here the swivel joint 28 is arranged above a pedal shaftbearing. Alternatively the swivel joint 28 may also be arranged in sucha way that its swiveling axis coincides with the rotational axis of thepedal shaft bearing.

The piston-cylinder assembly 9 at the front wheel 11 has a pneumaticcylinder 30 a, connected at its bottom to a guide tube 37 a by means ofa threaded connection. A tube 37 b with a piston rod 32 a attached to itis fitted to the steering assembly 7. A piston 31 a that is a slidingfit in the pneumatic cylinder 30 a is fitted to the bottom end of thepiston rod 32 a. The tube 37 b and the piston rod 32 a are adjustable inrelation to the guide tube 37 a and the pneumatic cylinder 30 a in alongitudinal direction, i.e. in the direction of arrow A.

The first cylinder space 34 a, i.e. the “plus chamber” is created by thepneumatic cylinder 30 a. The second cylinder space 35 a, i.e. the “minuschamber” is an annular cylinder space, which is created by the pneumaticcylinder 30 a, the piston rod 32 a and the piston 31 a. The bottomoutside area of the piston 31 delimiting a first cylinder space 34 a atthe top, is larger than the annular top outside area of the piston 31 athat delimits the second cylinder space 35 a at the bottom.

A drilled hole runs through the center of the piston 31 a and ends in ametal tube 51, which runs longitudinally upwards through the piston rod32 a to the steering assembly 7, and is connected at its top end to thecentral pressurizing line 12 (whereby the latter is connected to firstcylinder space 34 a via the metal tube 51 and the above drilled holerunning in a longitudinal direction).

A drilled hole connecting the second cylinder space 35 a to the tubularhollow space that lies between the inside wall of the piston rod 32 aand the outside wall of the metal tube 51 at the bottom end of thepiston rod 32 a, runs diagonally through the piston rod 32 a. Thistubular hollow space is connected to the second central pressurizingline 13 (which is thereby connected to the second cylinder space 35 avia the above hollow space between the piston rod 32 a and the metaltube 51, and the above diagonal drilled hole) at the top end of thepiston rod 32 a.

At the bottom end of the pneumatic cylinder 30 a there is a springelement 33 a. A float body 38 a has been fitted over the spring element33 a and seals off the first cylinder space 34 a from the cylinder spacein which the spring element 33 a is found. The latter may be of someelastic material; alternatively a helical coil spring, or air may beenclosed in the cylinder space underneath the float body 38 a as aspring element In alternative embodiment examples, no float body 38 ahas been provided; an O-ring that is not/not completely tight inrelation to the cylinder space 38 in which the spring element 33 a isfound may be provided as float body.

The second piston-cylinder assembly 14 includes a cylinder housing 38,into which the piston rod 19 is inserted longitudinally. The piston rodhas a pneumatic piston, which subdivides the cylinder housing 14 into afirst (front, left in the illustration) pneumatic cylinder chamber 41,and a second (back, i.e. right in the illustration) pneumatic cylinderchamber 42. The first pneumatic cylinder chamber 41 is designated the“plus chamber”, and the second pneumatic cylinder chamber 42 the “minuschamber”. The “minus chamber” 42 is an annular cylinder space thatconsists of the cylinder housing 38, the piston rod 19 and the pneumaticpiston. Here too the “plus chamber” 41 has a cross-sectional piston arealarger than the “minus chamber” by the cross-sectional area of thepiston rod 19. The first pneumatic cylinder chamber 41 is connected tothe first central pressurizing line 12, and the second pneumaticcylinder chamber 42 to the second central pressurizing line 13. Thecentral pressurizing lines 12 and 13 are also interconnectable via abypass line 12′, into which a check valve 15′ has been inserted.

Below, the operation of the adjustment devices is more closelyillustrated. First air is pumped into the adjustment devices. Before thepumping process starts, the valves 15, 15′ are opened, and then air isfor instance pumped into the “plus chamber” 41 of the secondpiston-cylinder assembly 14 via a valve fitted to the cylinder housing38 (not shown here) by means of an air pump. (Alternatively andparticularly when the float body 38 a is not (and/or not completelyairtight in relation to the cylinder space in which the spring element33 a is located, a valve may for instance be fitted to the bottom of thepneumatic cylinder 30 a through which air may be pumped into the “pluschamber” 34 a past the float body 38 a and the spring element.)

Then and/or even during pumping, the user of the bicycle may forinstance exert downward pressure on top of the saddle 3 a (oralternatively e.g. downward pressure on the handlebars 8) As a result,the piston rod 19 is forced away from the saddle rod 3 (or alternativelytowards the saddle rod 3). In the process, air for instance flows fromthe “plus chamber” 41 of the second piston-cylinder assembly 14 via thecentral pressurizing line 12 into the “plus chamber” 34 a of the firstpiston-cylinder assembly 9. This forces the pneumatic cylinder 30 a ofthe first piston-cylinder assembly 9 downwards, whereby air for instanceflows from the “minus chamber” 35 a of the first piston-cylinderassembly 9 via the central pressurizing line 13 into the “minus chamber”42 of the second piston-cylinder assembly 14.

As a result of the displacement of the piston rod 19 in the secondpiston-cylinder assembly, the rear axle arm 23 is rotatedcounter-clockwise around the swivel joint 28, whereby the rear wheel 27is “retracted”.

Furthermore the displacement of the pneumatic cylinder 30 a of the firstpiston-cylinder assembly 9 forces the guide tube 37 a downward as well,whereby the front wheel 11 is “extended”.

When the desired setting of the adjustment devices has been achieved,valve 15′ is first shut, and after that valve 15; during the firstoperation of the adjustment devices, downward pressure is for instancepreferably exerted on the saddle 3 a (and/or on the handlebars 8), untilthe pneumatic cylinder 30 a and the piston rod 19 have achieved theirrespective final settings (i.e. until each has been forced against itsrespective stop).

If the settings of the adjustment devices are changed, valve 15 of thefirst central pressurizing line 12 is opened again, and then, forinstance by the user of the bicycle pressing down on the handlebars 8(and/or alternatively on the saddle 3 a), the rear wheel 27 is“extended” and the front wheel 11 “retracted” again (and/oralternatively the rear wheel 27 is retracted and the front wheel 11extended even further).

Preferably the valve 15 is to be manufactured in the shape of a simplyoperable inching switch for this purpose.

The retracted setting of the rear wheel 27 and/or the extended settingof the front wheel 11 is particularly well suited to downhill riding,and the extended setting of the rear wheel 27 and/or the retractedsetting of the front wheel 11 is suited to uphill riding.

FIG. 9 shows a perspective representation of the steering head bearingsystem 5 of a bicycle from the right front. The steering head bearingsystem 5 may for instance be located at the common end of a longitudinalrod (not shown here), reaching backwards from the steering head bearingsystem 5 in a horizontal direction to the saddle of the bicycle, and adiagonal rod (not shown here) reaching out from the steering headbearing system 5 downward and back in the direction of the bicycle'spedal shaft bearing.

As shown in FIG. 9, two fork legs 9 a, 9 b, one front fork, and asteering assembly 7 are attached to the steering head bearing system 5of the bicycle. Each fork leg may for instance consist of a pneumaticheight-adjustable piston-cylinder assembly, at the bottom end of whichthe front wheel of the bicycle is suspended.

The piston-cylinder assembly may for instance have a pneumatic cylinderfitted at the lower end, mounted at its bottom end by means of athreaded connection to the guide tube 37 a surrounding the pneumaticcylinder. The piston-cylinder assembly may also have a piston rod at thetop, attached at its top end to a tube 37 b surrounding the piston rod.The piston rod has a piston at its bottom end, which is a sliding fit inthe pneumatic cylinder. The piston rod and the tube 37 b are adjustableupwards or downwards in relation to the guide tube 37 a and thepneumatic cylinder, in the direction of the arrow A.

At its top end the tube 37 b is attached to the steering head bearingsystem 5 by means of the upper and lower fork yoke elements 10 a, 10 b.The bottom fork yoke element 10 b has two tubular clamps 11 a, 11 b,through which the corresponding tube 37 b of each respective fork leg 9a, 9 b runs.

As shown in FIG. 10, each clamp 11 a, 11 b has been fitted with athreaded bolt reaching right across and through the slot machined intoeach of the clamps 11 a, 11 b. This allows each clamp 11 a, 11 b to becompressed (i.e. having its diameter reduced), so that the correspondingtube 37 b of each of the fork legs 9 a, 9 b is firmly held by eachcorresponding clamp 11 a, 11 b as shown in FIG. 9, as a result of whichthe respective fork leg 9 a, 9 b cannot be displaced upwards ordownwards in relation to the fork yoke element 10 b in the direction ofthe arrow A any longer.

As is further apparent from FIGS. 9 and 10, each fork yoke element 10 a,10 b has two drilled holes 12 a, 12 b, 12 c, 12 d with an essentiallycircular diameter, running through each fork from top to bottom to thelower yoke element 10 a, 10 b. One each of the above clamps 11 a, 11 bhas been incorporated in the drilled holes 12 a, 12 b of the bottom forkyoke element 10 b and the corresponding tube 37 b of each of the forklegs 9 a, 9 b directly into the drilled holes 12 c, 12 d of the upperfork yoke element 10 b.

According to FIG. 10 a slot runs back from each drilled hole 12 a, 12 b,12 c, 12 d—right through each corresponding fork yoke, from the top tothe bottom of each fork yoke element 10 a, 10 b—up to the respectiveback right and/or back left side wall of the corresponding fork yokeelements 10 a, 10 b. When the slot is compressed—e.g. by means of ascrew that is screwed into a threaded hole 13 a, 13 b running out fromthe fork yoke element side wall (with the threaded hole 13 a, 13 bapproximately perpendicular to the slot and bisecting it)—the diameterof each drilled d hole 12 a, 12 b, 12 c, 12 d is reduced.

Thereby the corresponding clamps 11 a, 11 b—at the bottom fork yokeelement 10 b—are compressed (and consequently, as seen in FIG. 9, thelower fork yoke element 10 b is locked onto the corresponding tube 37 bof the respective fork leg 9 a, 9 b, as described above), and/or thecorresponding inside wall of the drilled hole 12 c, 12 d directly forcedagainst the tube 37 b at the upper fork yoke element 10 b—there being noseparate clamps provided—thereby securing the corresponding tube 37 b atthe top fork yoke element 10 a.

Alternatively the clamps corresponding to the clamps 11 a, 11 b may beprovided at the upper fork yoke element 10 a—as they may be provided atthe bottom fork yoke element 10 b—or clamps corresponding to the clamps11 a, 11 b may for instance be provided only at the upper fork yokeelement 10 a, but not at the bottom fork yoke element 10 b, or the useof clamps at the bottom as well as at the top fork yoke elements 10 a,10 b may be dispensed with altogether.

According to FIG. 10, a steering tube 14 reaches up between the top andbottom fork yoke elements 10 a, 10 b in a vertical direction. As shownin FIG. 11 a, a second tube 15, which has a protruding flange 15 a, ismounted inside the steering tube 14. The second tube 15 is inserted fromthe bottom into another drilled hole 12 e that runs from bottom to topthrough the lower fork yoke element 10 b, and fitted into the drilledhole 12 e, whereby the flange 15 a seats into a correspondingly steppedcircular recess in the bottom fork yoke element 10 b at the second tube15.

A first ball bearing 16 a, which adjoins a first bearing shell 17 aupwards, diagonally upwards and outwards, and diagonally downwards andinwards, adjoins an annular, tapered flange protruding upwards from thelower fork yoke element 10 b (at a tapered bottom ball bearing section)and is fitted around the second tube 15. The first ball bearing 16 a andthe first bearing shell 17 a (and these adjoining parts) arecorrespondingly constructed and fitted as a reversed mirror image of asecond ball bearing 16 b and a second bearing shell 17 b, of which theconstruction and incorporation have been illustrated more closely withreference to FIG. 11 b.

Tapered ball bearings are used for the first and second ball bearings 16a, 16 b in the present embodiment. As an alternative, roller bearings,or any other suitable ball bearing that is able to absorb axial loads,may also be used. As is apparent from FIGS. 11 a and 11 b, a third tube18 has been fitted at the top of the steering tube 14, which has arearward protruding flange 18 a at its top. The third tube 18 isinserted from the top into a further drilled hole 12 f traversing theupper yoke element 10 a from top to bottom, and is screwed into acorresponding threaded bore 19 at the top end of the second tube 15. Asa result of the pre-tensioning achieved in this fashion, the flange 18 aon the third tube 18 is pressed against a correspondingly machinedstepwise tapered recess in the upper fork yoke element 10 a.

The second bearing shell 17 b is fitted into the steering tube 14,whereby the upper side of the steering tube 14 engages with thehorizontally protruding underside of the first section 19 a of thesecond bearing shell 17 b, and the inside of the steering tube 14 withthe outer side of a second section of the second bearing shell 17 b,which protrudes vertically downwards from the inside end of the firstbearing shell section. A third section 19 b protrudes downwards anddiagonally inwards from the bottom end of the second bearing shellsection, and from the bottom end of the third bearing shell section 19 ba fourth bearing shell section 19 c protrudes vertically inwards.

An annular, surrounding seal element with a T-shaped cross-section hasbeen fitted between the upper side of the first section 19 a of thesecond bearing shell 17 b and the underside of the upper fork yokeelement 10 a, whereby an upwards protruding section of the seal elementis fitted into an annular recess on the underside of the upper fork yokeelement 10 a, and a downwards protruding section of the seal elementinto an annular recess on the top side of the first section 19 a of thesecond bearing shell 17 b. Alternatively an O-ring with a circularcross-section or any other suitable seal element may also be used.

As also shown in FIG. 11 b, the second ball bearing 16 b is fittedaround the third tube 18. A vertical section the outer side of thesecond ball bearing 16 b engages with the inner side of the secondsection of the second bearing shell 17 b, and a diagonal downwards andinwards running section of the outer side of the second ball bearings 16a engages with the inner side of the third section 19 b of the secondbearing shell 17 b. In similar fashion the underside of the second ballbearing 16 b engages with the upper side of the fourth section 19 c ofthe second bearing shell 17 b.

As shown in FIG. 11 b, an annular flange 20 protrudes backwards from theunderside of the upper fork yoke element 10 a along the outer side ofthe third tube 18. The flange 20 is tapered down towards the bottom andoutside. In similar fashion—as also shown in FIG. 11 b—the inner side ofthe second ball bearing 16 b is tapered to the top and inside. Thecorresponding tapered limiting area of the second ball bearing 16 bengages with the correspondingly tapered limiting area of the flange 20of the upper fork yoke element 10 a.

After the third tube 18 has been screwed into the second tube 15, aclamping cone 21, of which the diameter is essentially the same as theinside diameter of the third tube 18, is fitted from the top into thethird tube 18. From the upper end of the clamping cone 21, a flange 21a, of which the underside engages with the annular upper area of thethird tube 18, and at the corresponding section with the above-mentionedstepped annular machined recess in the upper fork yoke element 10 a,protrudes outwards.

The third tube 18 has been provided at the top with two opposing slotsrunning vertically from the upper end of the third tube 18. The slotsperform a double function: on the one hand they provide an area where asuitable tool (e.g. a coin) may be inserted for screwing down the thirdtube 18; on the other, the slot of the third tube 18 can be spread bymeans of the clamping cone 21, so that its outside area is forcedagainst the inside area of the drilled hole 12 f of the upper fork yokeelement 10 a (and thereby the fork yoke element 10 a is forced againstthe second ball bearing 16 b, the second ball bearing 16 b against thesecond bearing shell 17 b, and the second bearing shell 17 b against thesteering tube 14).

Again referring to FIG. 9, a steering assembly 7—as previously describedabove—is fitted on the upper side of the upper fork yoke element 10 a.For this purpose, as seen in FIG. 10, each of the (relatively large)drilled holes 12 c, 12 d has been provided with the first and or secondset of (relatively smaller) threaded bores in a straight line on theinside to accept the tube 37 b.

The threaded bores in the two rows of threaded bores run down verticallyfrom the top of the upper fork yoke element 10 a. The first and secondrows of threaded bores lie parallel to each other, whereby the first rowof threaded bores has the same number of threaded bores as the secondrow of threaded bores (e.g. three, four or five threaded bores). Thecorresponding (first) threaded bores of the first and second row ofthreaded bores have an equal distance between each other as thecorresponding (second) threaded bores of the first and/or second row ofthreaded bores. In the same way, the corresponding (second) threadedbores of the row of first and second threaded bores have an equaldistance between each other as the (third) threaded bores of the row offirst and/or second threaded bores, &c.

In order to mount the steering mechanism 7 onto the fork yoke element 10a, the latter, as shown in FIG. 9 has two flanges left and right, ofsemi-circular diameter, of which the plane undersides engage with thesimilarly plane top of the fork yoke element 10 a. Corresponding drilledholes run from top to bottom through the flanges 21 and suitable screwsare inserted into them for fixing the steering mechanism 7. Depending onwhich of the (paired) corresponding threaded bores of the two rows ofthreaded bores on the upper fork yoke element 10 a the screws arescrewed into, the steering assembly 7 (and/or more precisely the flanges21) is attached more to the front or more to the back of the upper forkyoke element 10 a (cf. arrow B, FIG. 10).

From the semi-circular flanges 21—fixed to the fork yoke element 10a—corresponding tubular elements 22 protrude horizontally to the inside(FIG. 9). Corresponding spacers 24 are (first) fitted to the tubularelements 22 to revolve around the corresponding central axes of thetubular elements 22. For this purpose, the spacers 24 each has a first,horizontal drilled hole, into which the corresponding tubular element 22is fitted. In addition, each spacer 24 has a second, horizontal drilledhole 23, parallel to the first drilled hole, into which a rod of theactual handlebars of the bicycle may (first) be fitted so that they canto turn. By turning the spacer 24 around the central axis of the tubularelement 22, and/or by turning the handlebar rod around the central axisof the drilled holes 23, the handlebars can be positioned into thedesired angular setting (as well as setting them further forward or backby means of the appropriate fitting of the flanges 21).

As seen in FIG. 9, a slot runs from the second drilled hole 23 (to theback in the setting of the spacer 24 shown in FIG. 9) completely fromleft to right through the spacer 24 (somewhat in the direction the firstdrilled hole) up to the diagonal lower outside wall of the spacer 24. Insimilar fashion a slot runs from the first drilled hole (upwards in thesetting of the spacer 24 shown in FIG. 9) completely from left to rightthrough the spacer 24 (somewhat in the direction of the second drilledhole) up to the diagonal upper outside wall of the spacer 24.

In each case a threaded bore 25 a, 25 b runs more or less perpendicularto the slots—and transects them. When a screw is screwed into thethreaded bores, the slot running from the second horizontal drilled hole23, and the slot running from the first horizontal drilled hole may beclosed—in this way the diameter of the first, and the second drilledhole 23 is reduced. Thereby the corresponding spacer 24 is fixed inrelation to the corresponding tubular element 22, as is the rod of thehandlebars in relation to the corresponding spacer 24.

1. A bicycle adjustment device, in particular for adjusting the heightof the front wheel suspension, of the rear wheel suspension, of thesaddle or of the steering mechanism, wherein the adjustment device has adouble-acting piston/cylinder assembly with a first cylinder space (14a, 34 a) and a second cylinder space (15 a, 35 a), wherein the twocylinder spaces (14 a, 34 a; 15 a, 35 a) are interconnectable via afluid duct (16 a, 16 b, 12 a, 12 b), and/or whereby the first cylinderspace (14 a, 34 a) and the second cylinder space (15 a, 35 a) areseparated from each other by a piston, wherein the area of the pistondelimiting the first cylinder space (14 a, 34 a) is larger than the areaof the piston delimiting the second cylinder space (15 a, 35 a), and alocking mechanism (85 a, 11) for fixing the piston, in which the fluidduct (16 a, 16 b, 12 a, 12 b) can be closed by means of a shut-offmechanism (42), and in which the shut-off mechanism (42) is held in onesetting by means of air pressure, whereby the fluid duct (16 a, 16 b, 12a, 12 b) is blocked.
 2. A bicycle adjustment device according to claim1, in which the shut-off mechanism (42) can be actuated by means of anactuator.
 3. A bicycle adjustment device according to claim 1, in whichthe cylinder spaces (14 a, 34 a) are separated by means of a piston, andin which the fluid duct runs directly from the area of the pistondelimiting the first cylinder space (14 a, 34 a) through the piston tothe area of the piston delimiting the second cylinder.
 4. A bicycleadjustment device according to claim 3, in which the shut-off mechanismis placed inside the piston.
 5. A bicycle adjustment device according toclaim 1, in which the cylinder spaces (14 a, 34 a) are separated fromeach other by a piston, and in which the fluid duct runs from the areaof the piston delimiting the first cylinder space (14 a, 34 a) throughthe piston and the second cylinder space (15 a, 35 a) to an area that islocated outside the cylinder spaces.
 6. A bicycle adjustment deviceaccording to claim 5, in which the shut-off mechanism (42) is located inan area lying outside the cylinder spaces.
 7. A bicycle adjustmentdevice according to claim 1, in which the shut-off mechanism (42) has apiston, wherein a first outside area of the piston is connected to thefirst cylinder space (14 a, 34 a), and a second outside area of thepiston to the second cylinder space (15 a, 35 a) when the shut-offmechanisms (42) is in the closed position, and wherein the first outsidearea of the piston is larger than the second outside area.
 8. A bicycle,which has a bicycle adjusting device according to claim
 1. 9. A bicyclewith a frame and at least two bicycle adjustment devices according toclaim 1, wherein each of at least two adjustment devices has at least adouble-acting piston-cylinder assembly (9, 14) with a first cylinderspace (34 a, 41) and a second cylinder space (35 a, 42) each, and wherethe two first cylinder spaces (34 a, 41) are interconnectable through acentral pressurizing line (12) fitted for that purpose.
 10. A bicycleaccording to claim 9, whereby the first and second cylinder spaces (34a, 41, 35 a, 42) of the first and/or second piston-cylinder assembly (9,14) are separated from each other by a piston (31 a), which has a pistonrod (32 a), and whereby the central pressurizing line (12) isconnectable to the first and/or second cylinder space of eachpiston-cylinder assembly (9, 14) via a duct (51) that runs at leastpartially through the piston rod (32 a).
 11. A bicycle according toclaim 10, in which the line (51) runs at least partially in thelongitudinal direction of the piston rod (32 a).
 12. A bicycle accordingto claim 11, in which the line (51) essentially runs along the totallength of the piston rod (32 a).
 13. A bicycle according to claim 9, inwhich a further central pressurizing line (13), with which the twosecond cylinder areas (35 a, 42) are interconnectable, has beenadditionally provided.
 14. A bicycle according to claim 13, wherein theadditional central pressurizing line (12) is connectable with the firstand/or second cylinder spaces of the corresponding piston-cylinderassembly (9, 14) via a additional line that is led at least partlythrough the piston rod (32 a).
 15. A bicycle according to claim 14, inwhich the additional line runs at least partly in the longitudinaldirection of the piston rod (32 a).
 16. A bicycle according to claim 15,in which the additional line essentially extends along the entire lengthof the piston rod (32 a).
 17. A bicycle according to claim 15, in whichthe line (51) has been shaped as a tube.
 18. A bicycle according toclaim 17, in which the additional line between the tube and the pistonrod (32 a) has been shaped to lie flat.
 19. A bicycle according to claim9, whereby a shut-off mechanism (15) has been provided in the centralpressurizing line (12).
 20. A bicycle according to claim 13, in which noshut-off mechanism has been provided in the additional centralpressurizing line (13).
 21. A bicycle according to claim 13, whereby ashut-off mechanism has been provided in the additional centralpressurizing line (13).
 22. A bicycle according to claim 9, in which noshut-off mechanism has been provided in the central pressurizing line(12).
 23. A bicycle according to claim 9, in which the cylinder spaces(34 a, 41, 35 a, 42) are filled with a gas.
 24. A bicycle according toclaim 9, characterized in that no fixing mechanism, in particular nomechanical and/or hydraulic fixing mechanism has been provided for thefirst and/or the second piston-/cylinder assembly (9, 14).
 25. A bicycleaccording to claim 9, characterized in that the first and/or the secondpiston-cylinder assembly (9, 14) have exactly two cylinder areas.